An 18-month-old male presents with a two-day history of increasing
lethargy, anorexia, and vomiting. On physical examination, he was
found to be dehydrated and hypotonic, and was responsive only to
painful stimuli. Kussmaul's respirations were noted, and admission
blood gases revealed metabolic acidosis (arterial pH of 7.24).
Serum chemistries revealed a serum ammonia level of 147 umole/l.